JPH0423401A - Manufacture of positive temperature coefficient thermistor - Google Patents
Manufacture of positive temperature coefficient thermistorInfo
- Publication number
- JPH0423401A JPH0423401A JP2129495A JP12949590A JPH0423401A JP H0423401 A JPH0423401 A JP H0423401A JP 2129495 A JP2129495 A JP 2129495A JP 12949590 A JP12949590 A JP 12949590A JP H0423401 A JPH0423401 A JP H0423401A
- Authority
- JP
- Japan
- Prior art keywords
- mol
- grain
- oxidation treatment
- grain growth
- resistance
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 238000004519 manufacturing process Methods 0.000 title claims description 14
- 230000003647 oxidation Effects 0.000 claims abstract description 25
- 238000007254 oxidation reaction Methods 0.000 claims abstract description 25
- 239000000203 mixture Substances 0.000 claims description 21
- 238000000034 method Methods 0.000 claims description 9
- 230000007935 neutral effect Effects 0.000 claims description 7
- 239000002994 raw material Substances 0.000 claims description 6
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 5
- 229910052804 chromium Inorganic materials 0.000 claims description 5
- 229910052749 magnesium Inorganic materials 0.000 claims description 5
- 229910052748 manganese Inorganic materials 0.000 claims description 5
- 229910052758 niobium Inorganic materials 0.000 claims description 5
- 229910052760 oxygen Inorganic materials 0.000 claims description 5
- 239000001301 oxygen Substances 0.000 claims description 5
- 229910052761 rare earth metal Inorganic materials 0.000 claims description 5
- 229910052715 tantalum Inorganic materials 0.000 claims description 5
- 238000005245 sintering Methods 0.000 abstract description 20
- 230000015556 catabolic process Effects 0.000 abstract description 7
- 239000004065 semiconductor Substances 0.000 abstract description 7
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 abstract description 6
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 abstract description 6
- 230000002159 abnormal effect Effects 0.000 abstract description 5
- 229910002113 barium titanate Inorganic materials 0.000 abstract description 5
- 239000000463 material Substances 0.000 abstract description 4
- 239000000758 substrate Substances 0.000 abstract description 4
- 229910052681 coesite Inorganic materials 0.000 abstract description 3
- 229910052906 cristobalite Inorganic materials 0.000 abstract description 3
- 239000012212 insulator Substances 0.000 abstract description 3
- 239000000377 silicon dioxide Substances 0.000 abstract description 3
- 235000012239 silicon dioxide Nutrition 0.000 abstract description 3
- 229910052682 stishovite Inorganic materials 0.000 abstract description 3
- 229910052905 tridymite Inorganic materials 0.000 abstract description 3
- 230000007423 decrease Effects 0.000 abstract description 2
- 229910002370 SrTiO3 Inorganic materials 0.000 abstract 2
- 230000003247 decreasing effect Effects 0.000 abstract 1
- 239000006185 dispersion Substances 0.000 abstract 1
- 239000000370 acceptor Substances 0.000 description 14
- 230000000694 effects Effects 0.000 description 6
- 238000005036 potential barrier Methods 0.000 description 6
- 230000001590 oxidative effect Effects 0.000 description 5
- 230000004888 barrier function Effects 0.000 description 4
- 239000003795 chemical substances by application Substances 0.000 description 4
- 230000000052 comparative effect Effects 0.000 description 4
- OGIDPMRJRNCKJF-UHFFFAOYSA-N titanium oxide Inorganic materials [Ti]=O OGIDPMRJRNCKJF-UHFFFAOYSA-N 0.000 description 3
- 230000005343 Curie-Weiss law Effects 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 238000001354 calcination Methods 0.000 description 1
- 150000004649 carbonic acid derivatives Chemical class 0.000 description 1
- 150000001805 chlorine compounds Chemical class 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 238000005336 cracking Methods 0.000 description 1
- 238000010304 firing Methods 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 238000000465 moulding Methods 0.000 description 1
- 229910052573 porcelain Inorganic materials 0.000 description 1
- 239000000843 powder Substances 0.000 description 1
- 238000003756 stirring Methods 0.000 description 1
Landscapes
- Measuring Temperature Or Quantity Of Heat (AREA)
- Compositions Of Oxide Ceramics (AREA)
- Thermistors And Varistors (AREA)
Abstract
Description
【発明の詳細な説明】
倉鼠上二Ｕ里公１
本発明はＰＴＣサーミスタの製造方法、より詳細にはＢ
ａＴｉＯｓ系のＰＴＣサーミスタの製造方法に関する。[Detailed Description of the Invention] The present invention relates to a method for manufacturing a PTC thermistor, more specifically, B.
The present invention relates to a method of manufacturing an aTiOs-based PTC thermistor.
従冴四Ｊ支術
ＰＴＣサーミスタは、半導体特性を有する粒内とポテン
シャル障壁のある粒界とから成り立っている。粒内の抵
抗は温度に対しては不感であり、キュリー点以上の温度
において、ポテンシャル障壁が温度の上昇に伴い高くな
るので、それに従って粒界抵抗が指数関数的に増大し、
ＰＴＣ効果が発現する。粒界抵抗ｐは次式で表わされる
。The PTC thermistor consists of grains with semiconductor properties and grain boundaries with potential barriers. Resistance within grains is insensitive to temperature, and at temperatures above the Curie point, the potential barrier increases as temperature rises, so grain boundary resistance increases exponentially accordingly.
PTC effect is expressed. Grain boundary resistance p is expressed by the following formula.
ｐ＝ ｐｏｅＸｌ） （６） ・・・・・・
（１）φｃｃ ］。p= poeXl) (6) ・・・・・・
(1)φcc].
ε ただし、ρ。、ｋ、定数 φ：ポテンシャル障壁高さ Ｔ：絶対温度 ε：誘電率 をそれぞれ表わしている。ε However, ρ. ,k, constant φ: Potential barrier height T: Absolute temperature ε: Represents dielectric constant.
いま、上２（１）式を簡単にして、
ｐ＝Ａｅｘｐ（φ） と表わし、キュリ点ての障壁
高さ、φ＝Ｘの場合とφ＝１＋ｘとの場合を考えると、
φ＝Ｘの場合 ρ＝Ａ−ｅＸ
φ＝１＋ｘの場合 ｐ ＝ ２．７２Ａ・ｅＸ とな
る。Now, simplifying equation 2 (1) above, we express it as p=Aexp(φ), and considering the barrier height at the Curie point, φ=X and φ=1+x, we get φ=X. In the case ρ=A-eX In the case φ=1+x, p = 2.72A・eX.
ここで、キュリー点以上て障壁高さφが、キュリー・ワ
イスの法則に従う誘電率εの減少によって、同じ割合で
変化し、それぞれの高さが２倍になったとすると、
φ＝２ｘの場合 ｐ＝Ａ、ｅ２・φ＝２（１＋
Ｘ ｌ の場合 ρ＝ ７．３９Ａ−ｅ２Ｘとなり、抵
抗の変化率はそれぞれｅＸ倍、２．７２ ｘｅゝ倍とな
る。これより、キュリー点での障壁高さφが大きいほど
抵抗変化幅は大きいことがわかるが、キュリー点以下の
温度域での抵抗も大きくなってしまう。Here, if the barrier height φ above the Curie point changes at the same rate due to the decrease in permittivity ε according to the Curie-Weiss law, and each height doubles, then when φ = 2x p =A, e2・φ=2(1+
In the case of X l, ρ=7.39A-e2X, and the rate of change in resistance becomes eX times and 2.72 xeゝ times, respectively. From this, it can be seen that the larger the barrier height φ at the Curie point, the larger the resistance change width, but the resistance also increases in the temperature range below the Curie point.
従って、抵抗変化幅が大きく、かつ低抵抗であるＰＴＣ
サーミスタを得るためには、粒界の数を減らし、すなわ
ち粒径を大きくして、粒界−つ一つの障壁高さを大きく
してやると良いと考えられる。Therefore, PTC has a large resistance change range and low resistance.
In order to obtain a thermistor, it is thought that it is better to reduce the number of grain boundaries, that is, to increase the grain size, and to increase the barrier height of each grain boundary.
従来、低抵抗のＰＴＣサーミスタの製造方法として希土
類等の半導体化剤を０．５ ｍｏ１％以上加え、９００
〜１８００’Ｃの酸化性雰囲気下で仮焼後、成形し、還
元性雰囲気下において１３００〜１４５０℃で焼結させ
、さらに、１０００〜１８００℃で数分間酸化処理する
方法が提案されている（特開昭４８−３７６９３号公報
）。Conventionally, as a manufacturing method for low-resistance PTC thermistors, 900
A method has been proposed in which the material is calcined in an oxidizing atmosphere at ~1800'C, then shaped, sintered at 1300-1450°C in a reducing atmosphere, and then subjected to oxidation treatment at 1000-1800°C for several minutes ( (Japanese Unexamined Patent Publication No. 48-37693).
この方法によると、酸化性雰囲気下で焼結させると絶縁
化するような、０．５ ｍｏ１％以上の半導体化剤を添
加し、還元性雰囲気下で焼結させることにより、半導体
化剤を固溶させて、ドナーを供給し、粒内の抵抗率を１
０−１〜１Ｏ−２Ω・ｃｍ程度に下げている。その後、
酸化性雰囲気下において高温で短時間酸化処理を行なう
ことによって、粒界を酸化して、アクセプタを供給し、
粒界にポテンシャル障壁を形成している。According to this method, 0.5 mo1% or more of a semiconducting agent that becomes insulating when sintered in an oxidizing atmosphere is added, and the semiconducting agent is solidified by sintering in a reducing atmosphere. melt, supply a donor, and increase the resistivity within the grain to 1.
It is lowered to about 0-1 to 1O-2 Ω·cm. after that,
By performing oxidation treatment at high temperature for a short time in an oxidizing atmosphere, grain boundaries are oxidized and acceptors are supplied.
Potential barriers are formed at grain boundaries.
明が解？しようとする課題
上記したＰＴＣサーミスタの製造方法においでは、適切
な焼結助材が添加されていないために、焼結時に異常粒
成長を起こし、耐圧が悪くなるという課題があった。Ming is the answer? Problems to be Solved In the above-described method for manufacturing a PTC thermistor, there was a problem in that since an appropriate sintering aid was not added, abnormal grain growth occurred during sintering, resulting in poor pressure resistance.
また、アクセプタ供給源が添加されていないため、アク
セプタ生成効率が悪く、高温で酸化処理を行なわなけれ
ば十分なＰＴＣ効果を表わさないという課題があった。Further, since no acceptor supply source is added, the acceptor generation efficiency is poor, and there is a problem that a sufficient PTC effect cannot be exhibited unless oxidation treatment is performed at a high temperature.
さらに、これらの欠点のため、大電流、大電力回路では
使用できないという課題があった。Furthermore, due to these drawbacks, there was a problem that it could not be used in large current and large power circuits.
本発明は上記した課題に鑑みなされたものであって、低
抵抗でありながら、抵抗変化幅が大きく、しかも耐圧が
高く、大電力回路で使用できるようなＰＴＣサーミスタ
の製造方法を提供することを目的としている。The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a method for manufacturing a PTC thermistor that has a low resistance, a large resistance change range, a high breakdown voltage, and can be used in a high power circuit. The purpose is
課０を解？するための Ｐ
上記した目的を達成するために本発明に係るＢａＴｉＯ
３系のＰＴＣサーミスクの製造方法においては、ＢａＴ
１０３及び５ｒＴｘ（ｈからなる主原料１（１０ｍｏｌ
に対し、希土類元素、Ｎｂ及びＴａからなる群から選ば
れた少なくとも１種の元素を０．１ｍｏｌ以上、Ｔｉ０
ａを０．１〜２．０ ｍｏｌ 、 ５ｉｆ１．を０．１
〜５．０ ｍｏｌ、Ｍｎ、 Ｃｒ、 Ｍｇ等の元素のう
ち少なくとも１種の元素を０．０１〜０．１２ｍｏｌ添
加し、これらの混合物を還元性あるいは中性雰囲気下に
おいて焼結させ、この後酸素を含有する雰囲気下におい
て１１５０℃以上の温度範囲で酸化処理することを特徴
としている。Solved lesson 0? In order to achieve the above-mentioned purpose, BaTiO according to the present invention
In the method for manufacturing PTC thermistors of type 3, BaT
Main raw material 1 (10 mol
0.1 mol or more of at least one element selected from the group consisting of rare earth elements, Nb and Ta, Ti0
0.1 to 2.0 mol of a, 5if1. 0.1
~5.0 mol, 0.01 to 0.12 mol of at least one element among elements such as Mn, Cr, and Mg are added, and the mixture is sintered in a reducing or neutral atmosphere, and then It is characterized by performing oxidation treatment at a temperature range of 1150° C. or higher in an atmosphere containing oxygen.
毘−囲
上記した製造方法によれば、ＢａＴｉ０ｚ系のＰＴＣサ
ーミスクの製造方法において、ＢａＴｉＯ３及びＳｒＴ
ｉＯ３からなる主原料１００ ｍｏｌに対し、焼結助材
としてＴｉＯ２を０．１〜２．０ ｍｏｌ 、 ＳｉＯ
２を０１〜５０ｍｏｌ含むことにより、半導体内の異常
粒成長が抑えられ、均質な粒成長が促される。また、こ
れら焼結助材は、アクセプタ供給源を粒界に偏析させる
働きがあり、粒界のアクセプタ密度を向上させるので、
酸化処理を低温で行なうことができ、これによって、粒
界酸化の選択性が向上し、粒内な酸化絶縁体化させるこ
とがなく、従って、室温抵抗値を上昇させることがない
。According to the manufacturing method described above, in the manufacturing method of BaTiOz-based PTC thermistor, BaTiO3 and SrT
For 100 mol of the main raw material consisting of iO3, 0.1 to 2.0 mol of TiO2 as a sintering aid, SiO
By containing 01 to 50 mol of 2, abnormal grain growth within the semiconductor is suppressed and homogeneous grain growth is promoted. In addition, these sintering aids have the function of segregating the acceptor supply source at the grain boundaries, improving the acceptor density at the grain boundaries.
The oxidation treatment can be carried out at a low temperature, which improves the selectivity of grain boundary oxidation and prevents formation of oxidized insulators within the grains, thereby preventing an increase in room temperature resistance.
また、アクセプタ供給源としてＭｎ、 Ｃｒ、 Ｍｇ等
の元素のうち少なくとも１種の元素を０．Ｏ１〜０．１
２ｍｏｌ添加することにより、アクセプタ密度が向上し
、アクセプタ生成効率が良好になり、前記と同様の作用
が得られる。Furthermore, at least one element among elements such as Mn, Cr, and Mg is added as an acceptor supply source. O1~0.1
By adding 2 mol, the acceptor density is improved, the acceptor production efficiency is improved, and the same effect as described above can be obtained.
なお、Ｍｎ、 Ｃｒ、 Ｍｇ等の元素は、これらの元素
の化合物、例えば塩化物、炭酸化物、酸化物等によって
添加するのがよい。Note that elements such as Mn, Cr, and Mg are preferably added in the form of compounds of these elements, such as chlorides, carbonates, and oxides.
さらに、ＰＴＣサーミスタの抵抗は殆どが粒界抵抗であ
るが、半導体化剤として希土類元素、Ｎｂ及びＴａから
なる群から選ばれた少なくとも１種の元素を０．１ ｍ
ｏ１以上含むことにより、粒内の抵抗が調節されて室温
抵抗値の小さい半導体磁器が得られる。Furthermore, although most of the resistance of PTC thermistors is grain boundary resistance, at least one element selected from the group consisting of rare earth elements, Nb, and Ta is added as a semiconductor agent to 0.1 m
By containing o1 or more, the resistance inside the grains is adjusted and a semiconductor porcelain with a small room temperature resistance value can be obtained.
そして、これらの混合物を還元性あるいは中性雰囲気下
において焼結させ、この後酸素を含有する雰囲気下にお
いて１１５０℃以上の温度範囲で酸化処理することによ
り、粒界にポテンシャル障壁が形成され、抵抗変化幅が
大きくなり、ＰＴＣ効果を十分に有するサーミスタが得
られる。Then, by sintering these mixtures in a reducing or neutral atmosphere, and then oxidizing them in an oxygen-containing atmosphere at a temperature range of 1150°C or higher, potential barriers are formed at grain boundaries, increasing the resistance. The variation range becomes large, and a thermistor having a sufficient PTC effect can be obtained.
１嵐且反グ比藍舅
以下、本発明に係るＰＴＣサーミスクの製造方法の一実
施例について説明する。DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the method for manufacturing a PTC thermistor according to the present invention will be described below.
原料として、ＢａＴｉＯ３及び５ｒＴｉＯａからなる主
原料１００ ｍｏｌに対し、希土類元素、Ｎｂ及びＴａ
のうち少なくとも１種の元素を０．１ ｍｏ１以上、Ｔ
ｉＯ□を０１〜２．０ ｍｏｌ 、 ＳｉＯ２を０．１
〜５．０ ｍｏｌ、Ｍｎ、 Ｇｒ、 Ｍｇ等の元素のう
ち少なくとも１種の元素を０．０１〜０．１２ｍｏｌ添
加し、これらを混合した後、大気中で仮焼する。As raw materials, rare earth elements, Nb and Ta were added to 100 mol of the main raw material consisting of BaTiO3 and 5rTiOa.
At least one element of 0.1 mo1 or more, T
iO□ 01-2.0 mol, SiO2 0.1
~5.0 mol, 0.01 to 0.12 mol of at least one element among elements such as Mn, Gr, and Mg are added, and after mixing these, calcining is performed in the atmosphere.
次いで前記仮焼粉末をポットミル等を用いて粉砕した後
、バイングーを加えて攪拌混合し、成形した後、この成
形体を還元性あるいは中性雰囲気下において焼結させ、
その後、酸素を含有する雰囲気下において１１５０℃以
上の温度範囲で酸化処理する。Next, the calcined powder is pulverized using a pot mill or the like, and banhgu is added thereto and mixed with stirring. After molding, the molded body is sintered in a reducing or neutral atmosphere,
Thereafter, oxidation treatment is performed at a temperature range of 1150° C. or higher in an atmosphere containing oxygen.
さらに、この基板にＡｇ電極を形成してＰＴＣサーミス
クを作成する。Further, an Ag electrode is formed on this substrate to create a PTC thermistork.
第１表に示した組成において、種々の焼結条件及び酸化
処理条件で作成されたＰＴＣサーミスタの特性として室
温抵抗率、抵抗変化幅及び耐圧を測定した。焼結条件及
び酸化処理条件ならびに特性の測定結果を第２表に示し
た。With the compositions shown in Table 1, the room temperature resistivity, resistance change range, and breakdown voltage were measured as characteristics of PTC thermistors created under various sintering conditions and oxidation treatment conditions. Table 2 shows the sintering conditions, oxidation treatment conditions, and measurement results of properties.
（以下余白）
第１表中＊印は本発明の範囲外の組成のものを示し、そ
れ以外はすべて本発明の範囲内の組成のものである。ま
た、第２表中＊印は本発明の範囲外の組成のもの、ある
いは焼結条件及び酸化処理条件が本発明の範囲外のもの
を示しており、それ以外はすべて本発明の範囲内の組成
であり、かつ焼結条件及び酸化処理条件も本発明の範囲
内のものである。(The following is a blank space) In Table 1, the * mark indicates a composition outside the scope of the present invention, and all other compositions are within the scope of the present invention. In addition, the * mark in Table 2 indicates those with compositions outside the scope of the present invention, or those with sintering conditions and oxidation treatment conditions outside the scope of the present invention, and all other items are within the scope of the present invention. The composition, sintering conditions, and oxidation treatment conditions are also within the scope of the present invention.
第２表から明らかなように、組成が本発明の範囲内であ
る組成番号１においては、還元性雰囲気下で焼結しても
、酸化処理条件が適切でなければ室温抵抗率ρ２５が高
くなってしまう。一方、中性雰囲気下で焼成しても、酸
化処理が適切であれば還元性雰囲気下で焼結した場合と
同様に低い室温抵抗率ρ２５及び大きな抵抗変化幅ψが
得られる。As is clear from Table 2, in composition number 1, which is within the scope of the present invention, even if sintered in a reducing atmosphere, the room temperature resistivity ρ25 will increase unless the oxidation treatment conditions are appropriate. It ends up. On the other hand, even when sintered in a neutral atmosphere, if the oxidation treatment is appropriate, a low room temperature resistivity ρ25 and a large resistance change width ψ can be obtained, as in the case of sintering in a reducing atmosphere.
また、組成が本発明の範囲内である組成番号２では、大
気中で焼結し、酸化処理を行なわなかったものは、室温
抵抗率ρ２５が非常に高く、還元性雰囲気下で焼結し、
適切な酸化処理を施したものは室温抵抗率／）２５が低
くなることが示されている。ただし、酸化処理温度が低
過ぎると室温抵抗率／）２５は小さいが、抵抗変化幅ψ
も小さ（なってしまう。In addition, composition number 2, whose composition is within the scope of the present invention, has a very high room temperature resistivity ρ25 when sintered in the air and not subjected to oxidation treatment, and when sintered in a reducing atmosphere,
It has been shown that those subjected to appropriate oxidation treatment have a lower room temperature resistivity/)25. However, if the oxidation treatment temperature is too low, the room temperature resistivity /)25 will be small, but the resistance change width ψ
It also becomes small.
組成が本発明の範囲内である組成番号３ては、還元性雰
囲気下において焼結したものを酸化処理することで室温
抵抗率ρ２５を小さく、抵抗変化幅ψを大きくすること
ができる。しかし、大気中で焼結すると、組成が本発明
の範囲内であっても、室温抵抗率ｐ２６は非常に大きな
値となる。Composition number 3, whose composition is within the scope of the present invention, can be sintered in a reducing atmosphere and subjected to oxidation treatment to reduce the room temperature resistivity ρ25 and increase the resistance change width ψ. However, when sintered in the atmosphere, the room temperature resistivity p26 becomes a very large value even if the composition is within the range of the present invention.
また、比較例としてあげた組成番号４ては、還元性雰囲
気下で焼成し、適切な酸化処理を行なっても室温抵抗率
ρ２５が大きい。これは第１表で示されているように、
ＴｉＯ□及び５１０２といった焼結助材が加えられてい
ないためてあり、しかも抵抗変化幅ψが小さいのは、ア
クセプタ供給源となるＭｎが加えらていないことによる
。Furthermore, composition No. 4 given as a comparative example has a large room temperature resistivity ρ25 even if it is fired in a reducing atmosphere and subjected to appropriate oxidation treatment. As shown in Table 1, this
The reason why sintering aids such as TiO□ and 5102 are not added and the resistance change width ψ is small is because Mn, which serves as an acceptor supply source, is not added.
比較例としてあげた組成番号５も、ＴｌＯ２が多ずぎる
ために室温抵抗率ρ２５が高く、抵抗変化幅ψが小さ（
なっている。Composition No. 5 given as a comparative example also has a high room temperature resistivity ρ25 due to too much TlO2, and a small resistance change width ψ (
It has become.
組成番号６及び８では、組成が本発明の範囲内てあり、
焼成雰囲気及び酸化処理条件も適切であるので、室温抵
抗率ρ２５が小さく、抵抗変化幅ψが大きいものが得ら
れている。In composition numbers 6 and 8, the composition is within the scope of the present invention,
Since the firing atmosphere and oxidation treatment conditions were also appropriate, a product with a small room temperature resistivity ρ25 and a large resistance change width ψ was obtained.
比較例としてあげた組成番号７で示したように、ＳｉＯ
□が多すぎても室温抵抗率ｐ２５は高くなり、抵抗変化
幅ψが小さくなる。As shown in composition number 7 given as a comparative example, SiO
If □ is too large, the room temperature resistivity p25 becomes high and the resistance change width ψ becomes small.
また組成番号９のようにＭｎが多すぎると還元雰囲気下
で焼結してもわれが生じ、また、半導体化しない。Furthermore, if there is too much Mn as in composition number 9, sintering will cause cracking in a reducing atmosphere, and the material will not become a semiconductor.
更に耐圧については、ＰＴＣサーミスクを、その室温抵
抗値が０．５Ωとなるように作成して、比較した。比較
例としてあげたものの中にだけ耐圧の低いものがみられ
たが、本発明の範囲内のものについてはすべて耐圧の高
いものが得られた。Furthermore, with regard to withstand voltage, PTC thermistors were prepared so that their resistance at room temperature was 0.5Ω, and compared. Although some of the samples listed as comparative examples had low breakdown voltages, all of the samples within the scope of the present invention had high breakdown voltages.
このように、焼結助材及びアクセプタ供給源を適量添加
し、還元性あるいは中性雰囲気中で焼結し、十分均一に
粒成長させた後、酸化雰囲気下で、粒界だけを選択的に
酸化処理することにより高耐圧で、抵抗変化幅ψが大き
く、低抵抗なＰＴＣサーミスタを作成することができる
。In this way, after adding appropriate amounts of sintering aids and acceptor sources and sintering in a reducing or neutral atmosphere to achieve sufficiently uniform grain growth, grain boundaries are selectively grown in an oxidizing atmosphere. By performing the oxidation treatment, it is possible to create a PTC thermistor that has a high breakdown voltage, a large resistance change width ψ, and a low resistance.
光贋しΣ弘果
以上の説明により明らかなように、本発明にあっては、
ＢａＴｉＯ３系のＰＴＣサーミスタの製造方法において
、ＢａＴｉ０ａ及び５ｒＴｉＯａからなる主原料１００
ｍｏｌに対し、焼結助材としてＴｉＯ□を０．１〜２
．０ ｍｏｌ 、 ５ｉＯ７を０．１〜５．０ ｍｏｌ
添加するので、基板内の異常粒成長を抑え、均質な粒成
長を促すとともに、電極間の粒界数のバラツキを少なく
して、耐圧を向上させることができる。また、これら焼
結助材は、アクセプタ供給源を粒界に偏析させる働きが
あり、粒界のアクセプタ密度を向上させるので、酸化処
理を低温で行なうことができ、これによって、粒界酸化
の選択性が向上し、粒内が酸化絶縁体化されることがな
く、さらに、室温抵抗値を上昇させることもない。As is clear from the above explanation, in the present invention,
In the method for manufacturing a BaTiO3-based PTC thermistor, main raw material 100 consisting of BaTiOa and 5rTiOa
0.1 to 2 of TiO□ as a sintering aid to mol
．． 0 mol, 0.1-5.0 mol of 5iO7
Since it is added, it is possible to suppress abnormal grain growth within the substrate, promote homogeneous grain growth, and reduce variation in the number of grain boundaries between electrodes, thereby improving breakdown voltage. In addition, these sintering aids have the function of segregating acceptor sources to the grain boundaries, improving the acceptor density at the grain boundaries, allowing oxidation treatment to be performed at low temperatures, and thereby making it possible to select grain boundary oxidation. The properties are improved, the inside of the grains do not become an oxidized insulator, and the room temperature resistance value does not increase.
また、アクセプタ供給源としてＭｎ、 Ｃｒ、 Ｍｇ等
の元素のうち少なくとも１種の元素を０．０１〜０．１
２ｍｏｌ添加するので、アクセプタ密度を向上させるこ
とにより、前記と同様の効果を強めることができる。In addition, at least one element among elements such as Mn, Cr, and Mg is used as an acceptor supply source at 0.01 to 0.1
Since 2 mol is added, the same effect as described above can be enhanced by increasing the acceptor density.
さらに、ＰＴＣサーミスタの抵抗は殆どが粒界抵抗であ
るが、半導体化剤として希土類元素、Ｎｂ及びＴａから
なる群から選ばれた少なくとも１種の元素を０．１ ｍ
ｏ１以上含むことにより、粒内の抵抗を調節して室温抵
抗値の小さい基板を得ることができる。。Furthermore, although the resistance of a PTC thermistor is mostly grain boundary resistance, at least one element selected from the group consisting of rare earth elements, Nb, and Ta is added as a semiconductor agent to 0.1 m
By containing o1 or more, it is possible to adjust the resistance within the grains and obtain a substrate with a small room temperature resistance value. .
そして、これらの混合物を還元性あるいは中性雰囲気下
において焼結させ、この後酸素を含有する雰囲気下にお
いて１１５０℃以上の温度範囲で粒界だけを選択的に酸
化処理することにより、粒界にポテンシャル障壁を形成
して、抵抗変化幅を大きくすることができ、ＰＴＣ効果
を十分に有した低抵抗のサーミスタを得ることができる
。従って、大電力回路でも十分使用できるようなＰＴＣ
サーミスタを作成することができる。Then, these mixtures are sintered in a reducing or neutral atmosphere, and then only the grain boundaries are selectively oxidized in an oxygen-containing atmosphere at a temperature of 1150°C or higher. By forming a potential barrier, the width of resistance change can be increased, and a low resistance thermistor with sufficient PTC effect can be obtained. Therefore, PTC can be used sufficiently even in high power circuits.
A thermistor can be created.
特許出願人：住友金属工業株式会社Patent applicant: Sumitomo Metal Industries, Ltd.
Claims (1)
サーミスタの製造方法において、ＢａＴｉＯ＿３及びＳ
ｒＴｉＯ＿３からなる主原料１００ｍｏｌに対し、希土
類元素、Ｎｂ及びＴａからなる群から選ばれた少なくと
も１種の元素を０．１ｍｏｌ以上、ＴｉＯ＿２を０．１
〜２．０ｍｏｌ、ＳｉＯ＿２を０．１〜５．０ｍｏｌ、
Ｍｎ、Ｃｒ、Ｍｇ等の元素のうち少なくとも１種の元素
を０．０１〜０．１２ｍｏｌ添加し、これらの混合物を
還元性あるいは中性雰囲気下において焼結させ、この後
酸素を含有する雰囲気下において１１５０℃以上の温度
範囲で酸化処理することを特徴とする正特性サーミスタ
の製造方法。(1) Positive characteristics of BaTiO_3 system (hereinafter referred to as PTC)
In the thermistor manufacturing method, BaTiO_3 and S
For 100 mol of the main raw material consisting of rTiO_3, 0.1 mol or more of at least one element selected from the group consisting of rare earth elements, Nb and Ta, and 0.1 mol of TiO_2.
~2.0 mol, 0.1 to 5.0 mol of SiO_2,
Add 0.01 to 0.12 mol of at least one element among elements such as Mn, Cr, Mg, etc., sinter the mixture in a reducing or neutral atmosphere, and then sinter in an atmosphere containing oxygen. 1. A method for manufacturing a positive temperature coefficient thermistor, characterized in that oxidation treatment is performed at a temperature range of 1150° C. or higher.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2129495A JPH0423401A (en) | 1990-05-18 | 1990-05-18 | Manufacture of positive temperature coefficient thermistor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2129495A JPH0423401A (en) | 1990-05-18 | 1990-05-18 | Manufacture of positive temperature coefficient thermistor |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH0423401A true JPH0423401A (en) | 1992-01-27 |
Family
ID=15010894
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2129495A Pending JPH0423401A (en) | 1990-05-18 | 1990-05-18 | Manufacture of positive temperature coefficient thermistor |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0423401A (en) |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3348291A (en) * | 1965-07-26 | 1967-10-24 | Ingersoll Rand Co | Fluid operated stud driver tool |
| US3398446A (en) * | 1963-09-17 | 1968-08-27 | Sandvikens Jernberks Aktiebola | Device for applying traction-augmenting studs in tires for vehicles and the like |
| US6984355B2 (en) * | 1999-11-02 | 2006-01-10 | Murata Manufacturing Co., Ltd. | Semiconducting ceramic material, process for producing the ceramic material, and thermistor |
| KR100778105B1 (en) * | 2006-03-30 | 2007-11-22 | 한국과학기술원 | Method for making SrTiO3 varistor using grain boundary segregation |
| US20090253028A1 (en) * | 2007-02-20 | 2009-10-08 | Masaru Takagi | Temperature adjustment mechanism and vehicle |
| RU2713061C1 (en) * | 2016-12-08 | 2020-02-03 | Эндресс+Хаузер Ветцер Гмбх+Ко. Кг | Method and device for in situ calibration of thermometer |
-
1990
- 1990-05-18 JP JP2129495A patent/JPH0423401A/en active Pending
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3398446A (en) * | 1963-09-17 | 1968-08-27 | Sandvikens Jernberks Aktiebola | Device for applying traction-augmenting studs in tires for vehicles and the like |
| US3348291A (en) * | 1965-07-26 | 1967-10-24 | Ingersoll Rand Co | Fluid operated stud driver tool |
| US6984355B2 (en) * | 1999-11-02 | 2006-01-10 | Murata Manufacturing Co., Ltd. | Semiconducting ceramic material, process for producing the ceramic material, and thermistor |
| KR100778105B1 (en) * | 2006-03-30 | 2007-11-22 | 한국과학기술원 | Method for making SrTiO3 varistor using grain boundary segregation |
| US20090253028A1 (en) * | 2007-02-20 | 2009-10-08 | Masaru Takagi | Temperature adjustment mechanism and vehicle |
| RU2713061C1 (en) * | 2016-12-08 | 2020-02-03 | Эндресс+Хаузер Ветцер Гмбх+Ко. Кг | Method and device for in situ calibration of thermometer |
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